Fault-tolerant amplifier matrix

ABSTRACT

An amplifier matrix ( 112 ) has a plurality of inter-coupled matrix clusters ( 201 ), and a controller ( 106 ). The controller is programmed to detect ( 304 ) a fault in an amplification path of one of the matrix clusters, and update ( 316 ) vector relationships in the matrix clusters to minimize inter-sector isolation at the outputs of the matrix clusters.

FIELD OF THE INVENTION

This invention relates generally to amplification matrixes, and moreparticularly to a fault-tolerant amplifier matrix.

BACKGROUND OF THE INVENTION

Amplifier matrixes such as the well-known Butler matrix have been usedin cellular base stations for quite some time. An illustration of abutler matrix used to evenly distribute power amongst three amplifiers14 is provided in FIG. 1. Typically, a butler matrix has an input matrixportion 12, an output matrix portion 16, amplifiers 14 coupledtherebetween, and antennas 18 coupled to the outputs of the outputmatrix.

Under normal conditions, the amplified outputs of the input portion 12(i.e., outputs Y1 through Y3) have well-defined mathematicalrelationships such as, for example,${\overset{->}{Y}1} = {{{\frac{1}{\sqrt{3}} \cdot \overset{->}{S}}1\angle} - {90{^\circ}} + {{\frac{1}{\sqrt{3}} \cdot \overset{->}{S}}2{\angle 0{^\circ}}} + {{\frac{1}{\sqrt{3}} \cdot \overset{->}{S}}3\angle} - {180{^\circ}}}$${\overset{->}{Y}2} = {{{\frac{1}{\sqrt{3}} \cdot \overset{->}{S}}1{\angle 60{^\circ}}} + {{\frac{1}{\sqrt{3}} \cdot \overset{->}{S}}2\angle} - {90{^\circ}} + {\frac{1}{\sqrt{3}}\overset{->}{S}3\angle} - {150{^\circ}}}$${\overset{->}{Y}3} = {{{\frac{1}{\sqrt{3}} \cdot \overset{->}{S}}1\angle} - {150{^\circ}} + {{\frac{1}{\sqrt{3}} \cdot \overset{->}{S}}2\angle} - {180{^\circ}} + {{\frac{1}{\sqrt{3}} \cdot \overset{->}{S}}3\angle} - {120{^\circ}}}$

The outputs of the output portion 16 (i.e., outputs Z1 through Z3) havethe following mathematical relationships:${\overset{->}{Z}1} = {{{\frac{1}{\sqrt{3}} \cdot \overset{->}{Y}}1\angle} - {150{^\circ}} + {{\frac{1}{\sqrt{3}} \cdot \overset{->}{Y}}2{\angle 60{^\circ}}} + {{\frac{1}{\sqrt{3}} \cdot \overset{->}{Y}}3\angle} - {90{^\circ}}}$${\overset{->}{Z}2} = {{{\frac{1}{\sqrt{3}} \cdot \overset{->}{Y}}1\angle} - {180{^\circ}} + {{\frac{1}{\sqrt{3}} \cdot \overset{->}{Y}}2\angle} - {90{^\circ}} + {{\frac{1}{\sqrt{3}} \cdot \overset{->}{Y}}3{\angle 0{^\circ}}}}$${\overset{->}{Z}3} = {{{\frac{1}{\sqrt{3}} \cdot \overset{->}{Y}}1\angle} - {120{^\circ}} + {{\frac{1}{\sqrt{3}} \cdot \overset{->}{Y}}2\angle} - {150{^\circ}} + {{\frac{1}{\sqrt{3}} \cdot \overset{->}{Y}}3\angle} - {180{^\circ}}}$

Applying the Y equations to the Z equations produces the followingrelationships: $\begin{matrix}{{\overset{->}{Z}1} = {{{\frac{1}{3} \cdot \overset{->}{S}}1{\angle 120{^\circ}}} + {{\frac{1}{3} \cdot \overset{->}{S}}2\angle} - {150{^\circ}} + {{\frac{1}{3} \cdot \overset{->}{S}}3{\angle 30{^\circ}}} +}} \\{{{\frac{1}{3} \cdot \overset{->}{S}}1{\angle 120{^\circ}}} + {{\frac{1}{3} \cdot \overset{->}{S}}\quad 2\angle} - {30{^\circ}} + {{\frac{1}{3} \cdot \overset{->}{S}}3\angle} - {90{^\circ}} +} \\{{{\frac{1}{3} \cdot \overset{->}{S}}1{\angle 120{^\circ}}} + {{\frac{1}{3} \cdot \overset{->}{S}}2{\angle 90{^\circ}}} + {{\frac{1}{3} \cdot \overset{->}{S}}3{\angle 150{^\circ}}}} \\{= {\overset{->}{S}1{\angle 120{^\circ}}}}\end{matrix}$ $\begin{matrix}{{\overset{->}{Z}2} = {{{\frac{1}{3} \cdot \overset{->}{S}}{\angle 90{^\circ}}} + {{\frac{1}{3} \cdot \overset{->}{S}}2{\angle 180{^\circ}}} + {{\frac{1}{3} \cdot \overset{->}{S}}3{\angle 0{^\circ}}} +}} \\{{{\frac{1}{3} \cdot \overset{->}{S}}1} - {\angle 30{^\circ}} + {{\frac{1}{3} \cdot \overset{->}{S}}2{\angle 180{^\circ}}} + {{\frac{1}{3} \cdot \overset{->}{S}}3{\angle 120{^\circ}}} +} \\{{{\frac{1}{3} \cdot \overset{->}{S}}1\angle} - {150{^\circ}} + {{\frac{1}{3} \cdot \overset{->}{S}}2{\angle 180{^\circ}}} + {{\frac{1}{3} \cdot \overset{->}{S}}3\angle} - {120{^\circ}}} \\{= {\overset{->}{S}2{\angle 180{^\circ}}}}\end{matrix}$ $\begin{matrix}{{\overset{->}{Z}3} = {{{\frac{1}{3} \cdot \overset{->}{S}}1{\angle 150{^\circ}}} + {{\frac{1}{3} \cdot \overset{->}{S}}2\angle} - {120{^\circ}} + {{\frac{1}{3} \cdot \overset{->}{S}}3{\angle 60{^\circ}}} +}} \\{{{\frac{1}{3} \cdot \overset{->}{S}}1\angle} - {90{^\circ}} + {{\frac{1}{3} \cdot \overset{->}{S}}2{\angle 120{^\circ}}} + {{\frac{1}{3} \cdot \overset{->}{S}}3{\angle 60{^\circ}}} +} \\{{{\frac{1}{3} \cdot \overset{->}{S}}1{\angle 30{^\circ}}} + {{\frac{1}{3} \cdot \overset{->}{S}}2{\angle 0{^\circ}}} + {{\frac{1}{3} \cdot \overset{->}{S}}3{\angle 60{^\circ}}}} \\{= {\overset{->}{S}3{\angle 60{^\circ}}}}\end{matrix}$

These equations reflect a desired isolation characteristic at theoutputs of the output portion 16. FIG. 2 shows by way of examplereference 20, which depicts the code domain power of a UMTS (UniversalMobile Telecommunications Service) signal at the output portion 16 withall amplifiers operating properly. Under normal operating conditions,for example, the EVM (Error Vector Magnitude) of the UMTS signal ofoutput portion 16 is 5% and peak code domain error is −45.7 dB.

If, however, one of the amplifiers 14 experiences a fault which rendersit inoperable, the operation of the Butler matrix can be impactedseverely at all outputs of the output portion. This becomes evident inthe case where the Y1 amplifier is removed from operation. Under thesecircumstances, the Z equations result in the following relationships:${\overset{->}{Z}1} = {{\frac{2}{3}\overset{->}{S}1{\angle 120{^\circ}}} + {\frac{1}{3}\overset{->}{S}2{\angle 30{^\circ}}} + {\frac{1}{3}\overset{->}{S}3\angle} - {150{^\circ}}}$${\overset{->}{Z}2} = {{\frac{1}{3}\overset{->}{S}1\angle} - {90{^\circ}} + {\frac{2}{3}\overset{->}{S}2{\angle 180{^\circ}}} + {\frac{1}{3}\overset{->}{S}3{\angle 180{^\circ}}}}$${\overset{->}{Z}3} = {{\frac{1}{3}\overset{->}{S}\angle} - {30{^\circ}} + {\frac{1}{3}\overset{->}{S}2{\angle 60{^\circ}}} + {\frac{2}{3}\overset{->}{S}3{\angle 60{^\circ}}}}$

As should be evident from these equations, sector-to-sector isolationdegrades severely because of the residual terms between sectors.Consequently, a branch failure within a Butler matrix can cause majordegradation in waveform quality at the outputs of the output portion 16.This can cause considerable, if not complete, failure in radiocommunications to all sectors. FIG. 2 shows by way of example reference22, which depicts the code domain power of the UMTS signal at the outputportion 16 with amplifier Y1 disabled. Under these conditions, the codedomain noise has risen 20 dB compared to reference 20, and the EVM andpeak code domain error of the UMTS signal of output portion 16 havedegraded to 65.5% and −26.5 dB, respectively. A need therefore arisesfor a fault-tolerant amplifier matrix.

SUMMARY OF THE INVENTION

Embodiments in accordance with the invention provide a fault-tolerantamplifier matrix.

In a first embodiment of the present invention, an amplifier matrix hasa plurality of inter-coupled matrix clusters, and a controller. Thecontroller is programmed to detect a fault in an amplification path ofone of the matrix clusters, and update vector relationships in thematrix clusters to minimize inter-sector isolation at the outputs of thematrix clusters.

In a second embodiment of the present invention, a computer-readablestorage medium in an amplifier matrix has a plurality of matrixclusters. The storage medium includes computer instructions fordetecting a fault in an amplification path of one of the matrixclusters, and updating vector relationships in the matrix clusters tominimize inter-sector isolation at the outputs of the matrix clusters.

In a third embodiment of the present invention, a base station has acontroller, a receiver, and a transmitter. The transmitter has anamplifier matrix having a plurality of inter-coupled matrix clusters,and a plurality of antennas coupled to the outputs of the amplifiermatrix for radiating message signals to selective call radios (SCRs).The controller is programmed to detect a fault in an amplification pathof one of the matrix clusters, update vector relationships in the matrixclusters to minimize inter-sector isolation at the outputs of the matrixclusters, and radiate signals from the transmitter to one or more SCRs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a prior art Butler matrix in a cellularsystem.

FIG. 2 depicts measurements of the prior art Butler matrix of FIG. 1before and after a fault in said system.

FIG. 3 is a block diagram of a base station in accordance with anembodiment of the present invention.

FIGS. 4 and 5 depict block diagrams of an amplifier matrix of the basestation in accordance with an embodiment of the present invention.

FIG. 6 depicts a flowchart of a method operating in a transmitter of thebase station in accordance with embodiments of the present invention.

FIG. 7 depicts a table comparing operating results of the transmitterbefore and after a fault is corrected in accordance with embodiments ofthe present invention.

DETAILED DESCRIPTION

While the specification concludes with claims defining the features ofembodiments of the invention that are regarded as novel, it is believedthat the embodiments of the invention will be better understood from aconsideration of the following description in conjunction with thefigures, in which like reference numerals are carried forward.

FIG. 3 is a block diagram of a base station 100 in accordance with anembodiment of the present invention. The base station 100 comprises aconventional receiver 102 for intercepting signals from one or moreselective call radios (SCRs) 101, a transmitter 104 for radiatingmessage signals directed to the SCRs 101, and a conventional controller106. The controller 106 can utilize one or more computing devices suchas microprocessors, and/or DSPs (Digital Signal Processors) each withassociated storage media for controlling operations of the receiver 102and the transmitter 104.

The transmitter 104 comprises an amplifier matrix 112 coupled to aplurality of antennas 114 for radiating message signals to selectivecall radios (SCRs). Signals delivered to the amplifier matrix 112 can bebaseband signals generated by the controller 106 having an embeddedmessage intended for processing by a user of the SCR 101.

The foregoing components of the base station 100 can be powered by aconventional power supply 108.

FIGS. 4 and 5 depict block diagrams of the amplifier matrix 112 inaccordance with an embodiment of the present invention. The amplifiermatrix 112 comprises a plurality of inter-coupled matrix clusters 201(only two are shown for illustration). Each matrix cluster 201 comprisesa digital matrix 202, an analog matrix 204, and up-converted amplifiers206 coupled therebetween. The outputs of the analog matrix 204 arecoupled to the antennas 114, and can be individually decoupled to aconventional load 208. The up-converted amplifiers 206 can comprise aconventional up-converter 220 and a corresponding conventional amplifier222 as shown in FIG. 5. Utilizing conventional technology, theup-converter 220 transforms the operating frequency of the basebandsignals supplied by the digital matrix 202 to a carrier signal operatingat a carrier frequency such as, for example, 880 MHz (a typical cellularcarrier band). The amplifiers 222 supply to the analog matrix 204amplified up-converted signals for further processing.

FIG. 6 depicts a flowchart of a method 300 operating in the transmitter104 of the base station 100 in accordance with embodiments of thepresent invention. Method 300 begins with step 302 where the controller106 utilizes conventional methods to monitor faults in the amplificationpaths of the matrix clusters 201 shown in FIG. 4. If a no fault isdetected in step 304, the controller 106 proceeds to step 306 where itradiates signals to the SCRs 101 in accordance with normal operations.If, on the other hand, a fault is detected (such as an inoperableamplifier 206), the controller 106 asserts an alarm in step 308. Thealarm can, for example, notify personnel of an infrastructure carriermanaging the base station 100 of the fault. The notification can be anemail, an over-the-air message, or other form of notification suitablefor the carrier's business operations.

In step 309, the controller 106 is programmed to select an input of thedigital matrix 202 having the lowest power and a corresponding output ofthe analog matrix 204. In steps 309, 310 and 312, the controller 106takes a first mitigation step which is to decouple the antenna from theoutput of the analog matrix 204 selected in step 309 of the affectedmatrix cluster 201A and apply a load to the decoupled output. Thesesteps are shown in cluster 201 A of FIG. 4 on output Z3. The controller106 can be further programmed in step 314 to nullify the input (S3) ofthe digital matrix 202 selected in step 309 corresponding to thedecoupled output Z3. From these steps, the controller 106 in step 316updates vector relationships in the matrix clusters 201A and 201B tominimize inter-sector isolation at the outputs of the matrix clusters.

Steps 310 through 316 can be explained mathematically from theillustrations of FIG. 4. For the affected cluster 201A, the followingrelationships apply:${\overset{->}{Y}}_{2A} = {{{Y_{S_{1}A} \cdot {\overset{->}{S}}_{1}}{\angle 90{^\circ}}} + {{Y_{S_{2}A} \cdot {\overset{->}{S}}_{2}}\angle} - {120{^\circ}} + {0 \cdot {\overset{->}{S}}_{3}}}$${\overset{->}{Y}}_{3A} = {{{Y_{S_{1}A} \cdot {\overset{->}{S}}_{1}}{\angle 180{^\circ}}} + {{Y_{S_{2}A} \cdot {\overset{->}{S}}_{2}}\angle} - {150{^\circ}} + {0 \cdot {\overset{->}{S}}_{3}}}$$S_{1{A\_ AvailablePower}} = {\left( \frac{S_{1{A\_ OriginaPowerl}}}{S_{1{A\_ OriginalPower}} + S_{2{A\_ OriginalPower}}} \right)\left( \frac{{CLA\_ Total}{\_ Available}{\_ Power}}{2} \right)}$$S_{2{A\_ AvailablePower}} = {\left( \frac{S_{\quad{2\quad{A\_ OriginalPower}}}}{S_{1{A\_ OriginalPower}} + S_{\quad{2\quad{A\_ OriginalPower}}}} \right)\quad\left( \frac{{CLA\_ Total}{\_ Available}{\_ Power}}{2} \right)}$S_(1_APower) = MIN(S_(1A_OriginalPower), S_(1A_AvailablePower))S_(2A_Power) = MIN(S_(2A_OriginalPower), S_(2A_AvailablePower))$Y_{S_{1}A} = \sqrt{\frac{S_{1{A\_ Power}}}{S_{1{A\_ OriginalPower}}}}$$Y_{S_{2}A} = \sqrt{\frac{S_{2{A\_ Power}}}{S_{2{A\_ OriginalPower}}}}$

In the above equations, CLA represents matrix cluster 201A. The term“CLA Total Available Power” refers to the maximum summed powercapability of the enabled amplification paths. This term is divided bytwo because half of the power will be dissipated in a load, while theother half is available to be radiated at the antennae. For theunaffected matrix cluster 201B, the following relationships apply:${\overset{->}{Y}}_{1B} = {{{Y_{S_{1}B} \cdot {\overset{->}{S}}_{1}}\angle} - {90{^\circ}} + {{Y_{S_{2}B} \cdot {\overset{->}{S}}_{2}}{\angle 0{^\circ}}} + {{Y_{S_{3}B} \cdot {\overset{->}{S}}_{3}}\angle} - {180{^\circ}}}$${\overset{->}{Y}}_{2B} = {{{Y_{S_{1}B} \cdot {\overset{->}{S}}_{1}}{\angle 60{^\circ}}} + {{Y_{S_{2}B} \cdot {\overset{->}{S}}_{2}}\angle} - {90{^\circ}} + {{Y_{S_{3}B} \cdot {\overset{->}{S}}_{3}}\angle} - {150{^\circ}}}$${\overset{->}{Y}}_{3B} = {{{Y_{S_{1}B} \cdot {\overset{->}{S}}_{1}}\angle} - {150{^\circ}} + {{Y_{S_{2}B} \cdot {\overset{->}{S}}_{2}}\angle} - {180{^\circ}} + {{Y_{S_{3}B} \cdot {\overset{->}{S}}_{3}}\angle} - {120{^\circ}}}$S_(1B_DesiredPower) = (Total_Original_S1_Frame_Power) − S_(1A_Power)S_(2B_DesiredPower) = (Total_Original_S2_Frame_Power) − S_(2A_Power)S_(3B_DesiredPower) = (Total_Original_S3_Frame_Power) − S_(3A_Power)$S_{1{B\_ AvailablePower}} = {\left( \frac{S_{1{B\_ DesiredPower}}}{S_{1{B\_ DesiredPower}} + S_{2{B\_ DesiredPower}} + S_{3{B\_ DesiredPower}}} \right)\left( {{CLB\_ Total}{\_ Available}{\_ Power}} \right)}$$S_{2{B\_ AvailablePower}} = {\left( \frac{S_{2{B\_ DesiredPower}}}{S_{1{B\_ DesiredPower}} + S_{2{B\_ DesiredPower}} + S_{3{B\_ DesiredPower}}} \right)\left( {{CLB\_ Total}{\_ Available}{\_ Power}} \right)}$$S_{3{B\_ AvailablePower}} = {\left( \frac{S_{3{B\_ DesiredPower}}}{S_{1{B\_ DesiredPower}} + S_{2{B\_ DesiredPower}} + S_{3{B\_ DesiredPower}}} \right)\left( {{CLB\_ Total}{\_ Available}{\_ Power}} \right)}$S_(1B_Power) = MIN(S_(1B_DesiredPower), S_(1B_DesiredPower))S_(2B_Power) = MIN(S_(2B_DesiredPower), S_(2B_DesiredPower))S_(3B_Power) = MIN(S_(2B_DesiredPower), S_(2B_DesiredPower))$Y_{S_{1}B} = \sqrt{\frac{S_{1{B\_ Power}}}{3S_{1{B\_ OriginalPower}}}}$$Y_{S_{2}B} = \sqrt{\frac{S_{2{B\_ Power}}}{3S_{2{B\_ OriginalPower}}}}$$Y_{S_{3}B} = \sqrt{\frac{S_{3{B\_ Power}}}{3s_{3{B\_ OriginalPower}}}}$

Similar to the prior equations, CLB represents matrix cluster 201B.

FIG. 7 depicts a table comparing operating results of the transmitter104 before and after the fault is corrected in accordance method 300described earlier. In this table, sectors S1 through S3 are assumed tooutput 40, 30, and 10 Watts, respectively, and each amplification pathhas a maximum power capability of 20 W. Applying the above equations tothe affected matrix cluster 201A with these assumptions leads to thefollowing results:$S_{1{A\_ AvailablePower}} = {{\left( \frac{S_{1{A\_ OriginalPower}}}{S_{1{A\_ OriginalPower}} + S_{2{A\_ OriginalPower}}} \right)\left( \frac{{CLA\_ Total}{\_ Available}{\_ Power}}{2} \right)} = {{\left( \frac{20}{35} \right)\left( \frac{40}{2} \right)} = {11.4\quad W}}}$$S_{2{A\_ AvailablePower}} = {{\left( \frac{S_{2{A\_ OriginalPower}}}{S_{1{A\_ OriginalPower}} + S_{2{A\_ OriginalPower}}} \right)\quad\left( \frac{{CLA\_ Total}{\_ Available}{\_ Power}}{2} \right)} = {{\left( \frac{15}{35} \right)\left( \frac{40}{2} \right)} = {8.6\quad W}}}$S_(1A_Power) = MIN(S_(1A_OriginalPower), S_(1A_AvailablePower)) = 11.4  WS_(2A_Power) = MIN(S_(2A_OriginalPower), S_(2A_AvailablePower)) = 8.6  W$Y_{S_{1}A} = {\sqrt{\frac{S_{1{A\_ Power}}}{S_{1{A\_ OriginalPower}}}} = 0.756}$$Y_{S_{2}A} = {\sqrt{\frac{S_{2{A\_ Power}}}{S_{2{A\_ OriginalPower}}}} = 0.756}$${\overset{->}{Y}}_{2A} = {{{0.756 \cdot {\overset{->}{S}}_{1}}{\angle 90{^\circ}}} + {{0.756 \cdot {\overset{->}{S}}_{2}}\angle} - {120{^\circ}} + {0 \cdot {\overset{->}{S}}_{3}}}$${\overset{->}{Y}}_{3A} = {{{0.756 \cdot {\overset{->}{S}}_{1}}{\angle 180{^\circ}}} + {{0.756 \cdot {\overset{->}{S}}_{2}}\angle} - {150{^\circ}} + {0 \cdot {\overset{->}{S}}_{3}}}$${\overset{->}{Z}}_{1A} = {{{{0.436 \cdot {\overset{->}{S}}_{1}}{\angle 150{^\circ}}} + {{0.436 \cdot {\overset{->}{S}}_{2}}\angle} - {60{^\circ}} + {{0.436 \cdot {\overset{->}{S}}_{1}}{\angle 90{^\circ}}} + {{0.436 \cdot {\overset{->}{S}}_{2}}{\angle 120{^\circ}}}} = {{0.756 \cdot {\overset{->}{S}}_{1}}{\angle 120{^\circ}}}}$${\overset{->}{Z}}_{2A} = {{{{0.436 \cdot {\overset{->}{S}}_{1}}{\angle 0{^\circ}}} + {{0.436 \cdot {\overset{->}{S}}_{2}}{\angle 150{^\circ}}} + {{0.436 \cdot {\overset{->}{S}}_{1}}{\angle 180{^\circ}}} + {{0.436 \cdot {\overset{->}{S}}_{2}}\angle} - {150{^\circ}}} = {{0.756 \cdot {\overset{->}{S}}_{2}}{\angle 180{^\circ}}}}$

Applying the above equations to the unaffected matrix cluster 201B withthese assumptions leads to the following results:S_(1B_DesiredPower) = (Total_Original_S1_Frame_Power) − S_(1A_Power) = 40 − 11.4 = 28.6  WS_(2B_DesiredPower) = (Total_Original_S2_Frame_Power) − S_(2A_Power) = 30 − 8.6 = 21.4  WS_(3B_DesiredPower) = (Total_Original_S3_Frame_Power) − S_(3A_Power) = 10 − 0 = 10  W$S_{1{B\_ AvailablePower}} = {{\left( \frac{S_{1{B\_ DesiredPower}}}{S_{1{B\_ DesiredPower}} + S_{2{B\_ DesiredPower}} + S_{3{B\_ DesiredPower}}} \right)\left( {{CLB\_ Total}{\_ Available}{\_ Power}} \right)} = {{\left( \frac{28.6}{60} \right)(60)} = {28.6\quad\text{W}}}}$$S_{2{B\_ AvailablePower}} = {{\left( \frac{S_{2{B\_ DesiredPower}}}{S_{1{B\_ DesiredPower}} + S_{2{B\_ DesiredPower}} + S_{3{B\_ DesiredPower}}} \right)\left( {{CLB\_ Total}{\_ Available}{\_ Power}} \right)} = {{\left( \frac{21.4}{60} \right)(60)} = {21.4\quad\text{W}}}}$$S_{3{B\_ AvailablePower}} = {{\left( \frac{S_{3{B\_ DesiredPower}}}{S_{1{B\_ DesiredPower}} + S_{2{B\_ DesiredPower}} + S_{3{B\_ DesiredPower}}} \right)\left( {{CLB\_ Total}{\_ Available}{\_ Power}} \right)} = {{\left( \frac{10}{60} \right)(60)} = {10\quad\text{W}}}}$S_(1B_Power) = MIN(S_(1B_DesiredPower), S_(1B_AvailablePower)) = 28.6  WS_(2B_Power) = MIN(S_(2B_DesiredPower), S_(2B_AvailablePower)) = 21.4  WS_(3B_Power) = MIN(S_(2B_DesiredPower), S_(2B_AvailablePower)) = 10  W$Y_{S_{1}B} = {\sqrt{\frac{S_{1{B\_ Power}}}{3S_{1{B\_ OriginalPower}}}} = {\sqrt{\frac{28.6}{60}} = 0.69}}$$Y_{S_{2}B} = {\sqrt{\frac{S_{2{B\_ Power}}}{3S_{2{B\_ OriginalPower}}}} = {\sqrt{\frac{21.4}{45}} = 0.69}}$$Y_{S_{3}B} = {\sqrt{\frac{S_{3{B\_ Power}}}{3S_{3{B\_ OriginalPower}}}} = {\sqrt{\frac{10}{15}} = \sqrt{\frac{2}{3}}}}$${\overset{->}{Y}}_{1B} = {{{0.69 \cdot {\overset{->}{S}}_{1}}\angle} - {90{^\circ}} + {{0.69 \cdot {\overset{->}{S}}_{2}}{\angle 0{^\circ}}} + {{\sqrt{\frac{2}{3}} \cdot {\overset{->}{S}}_{3}}\angle} - {180{^\circ}}}$${\overset{->}{Y}}_{2B} = {{{0.69 \cdot {\overset{->}{S}}_{1}}{\angle 60{^\circ}}} + {{0.69 \cdot {\overset{->}{S}}_{2}}\angle} - {90{^\circ}} + {{\sqrt{\frac{2}{3}} \cdot {\overset{->}{S}}_{3}}\angle} - {150{^\circ}}}$${\overset{->}{Y}}_{3B} = {{{0.69 \cdot {\overset{->}{S}}_{1}}\angle} - {150{^\circ}} + {{0.69 \cdot {\overset{->}{S}}_{2}}\angle} - {180{^\circ}} + {{\sqrt{\frac{2}{3}} \cdot {\overset{->}{S}}_{3}}\angle} - {120{^\circ}}}$${\overset{->}{Z}}_{1B} = {{1.2 \cdot {\overset{->}{S}}_{1}}{\angle 120{^\circ}}}$${\overset{->}{Z}}_{2B} = {{1.2 \cdot {\overset{->}{S}}_{2}}{\angle 180{^\circ}}}$${\overset{->}{Z}}_{3B} = {\sqrt{2 \cdot}{\overset{->}{S}}_{3}{\angle 60{^\circ}}}$

FIG. 7 shows the results of these calculations, assuming ideal combiningof clusters A and B, and the results if no modification takes place inaccordance with method 300. If the matrix clusters 201A and 201B remainunmodified (i.e., method 300 is not applied), cluster 201A will generateat 8.9 Watts at Z1 for sector 1 (S1), 6.7 Watts at Z2 for S2, and 2.2Watts at Z3 for S3. Each of Z1 through Z3 for non-corresponding sectorswill receive a total noise term ranging between 2.3 Watts and 3.9 Wattsas indicated in FIG. 7. Matrix cluster 201B, on the other hand, willgenerate 20 Watts at Z1 for S1, 15 Watts at Z2 for S2, and 5 Watts at Z3for S3. All other non-corresponding sectors will receive 0 Watts asexpected. The resulting desired sector power at Z1 is 28.9 Watts with anisolation of −11 dBc, the resulting desired sector power at Z2 is 21.7Watts with an isolation of −8.9 dBc, and the resulting desired sectorpower at Z3 is 7.2 Watts with an isolation of −2.7 dBc. Generally, anisolation less than −15 dBc is considered unacceptable. Present systemsare requiring isolation as high as −25 dBc. Clearly, the unmodifiedmatrix cluster 201A falls short of this goal.

Compare, on the other hand, the performance of the clusters 201A and201B modified in accordance with method 300. Cluster 201A will generate11.4 Watts at Z1 for S1, 8.6 Watts for Z2 for S2, and 0 Watts at Z3 forS3. Each of Z1 through Z3 for non-corresponding sectors will generate 0Watts of noise. Matrix cluster 201B will generate 28.6 Watts at Z1 forS1, 21.4 Watts at Z2 for S2, and 10 Watts at Z3 for S3. All othernon-corresponding sectors will generate 0 Watts also. The resultingdesired sector power at Z1 is 40 Watts, at Z2 it is 30 Watts, and at Z3it is 10 Watts with ideally infinite dBc isolation across all sectors.Obviously, the results presented in the modified clusters 201A and 201Bis far superior to prior art systems with no fault-tolerance capability.

It should be evident to an artisan with skill in the art that portionsof embodiments of the present invention can be embedded in a computerprogram product, which comprises features enabling the implementationstated above. A computer program in the present context means anyexpression, in any language, code or notation, of a set of instructionsintended to cause a system having an information processing capabilityto perform a particular function either directly or after either or bothof the following: a) conversion to another language, code or notation;b) reproduction in a different material form.

It should also be evident that the present invention can be realized inhardware, software, or combinations thereof. Additionally, the presentinvention can be embedded in a computer program, which comprises all thefeatures enabling the implementation of the methods described herein,and which enables said devices to carry out these methods. A computerprogram in the present context means any expression, in any language,code or notation, of a set of instructions intended to cause a systemhaving an information processing capability to perform a particularfunction either directly or after either or both of the following: a)conversion to another language, code or notation; b) reproduction in adifferent material form. Additionally, a computer program can beimplemented in hardware as a state machine without conventional machinecode as is typically used by CISC (Complex Instruction Set Computers)and RISC (Reduced Instruction Set Computers) processors.

The present invention may also be used in many arrangements. Forexample, the digital and analog matrixes 202 and 204 can utilize otherdimensions such as, for example, 3 by 3, 4 by 4, 6 by 6, or 8 by 8matrixes, just to mention a few. Method 300 in FIG. 6 can be simplifiedby integrating steps 314 and 316 in a single step. Portions of theembodiments described above can also be reconfigured to work with othermatrix implementations. For instance, instead of using a digital matrix202 operating at baseband, a programmable analog input matrix could beused. The up-converters 220 in this configuration could be placed priorto the analog input matrix, and the vector relationships could becontrolled via a combination of gain and phase adjusters such thatsimilar results as described above can be attained. Thus, although thedescription is made for particular arrangements and methods, the intentand concept of the invention is suitable and applicable to otherarrangements and applications not described herein. The embodiments ofmethod 300 therefore can in numerous ways be modified with additionsthereto without departing from the spirit and scope of the invention.

Accordingly, the described embodiments ought to be construed to bemerely illustrative of some of the more prominent features andapplications of the invention. It should also be understood that theclaims are intended to cover the structures described herein asperforming the recited function and not only structural equivalents.Therefore, equivalent structures that read on the description are to beconstrued to be inclusive of the scope of the invention as defined inthe following claims. Thus, reference should be made to the followingclaims, rather than to the foregoing specification, as indicating thescope of the invention.

1. An amplifier matrix, comprising: a plurality of inter-coupled matrixclusters; and a controller programmed to: detect a fault in anamplification path of one of the matrix clusters; and update vectorrelationships in the matrix clusters to minimize inter-sector isolationat outputs of the matrix clusters.
 2. The amplifier matrix of claim 1,wherein each matrix cluster comprises: a digital matrix; a plurality ofup-converters coupled to the outputs of the digital matrix; a pluralityof amplifiers coupled to the outputs of the up-converters; and an analogmatrix coupled to the outputs of the plurality of amplifiers.
 3. Theamplifier matrix of claim 2, comprising a plurality of antennas coupledto the outputs of the analog matrix for radiating message signals to aplurality of selective call radios (SCRs).
 4. The amplifier matrix ofclaim 3, wherein the controller is programmed to: decouple an antennafrom one of the outputs of the analog matrix of the affected matrixcluster; and apply a load to said decoupled output.
 5. The amplifiermatrix of claim 4, wherein the controller is programmed to nullify aninput of the digital matrix corresponding to the decoupled output. 6.The amplifier matrix of claim 5, wherein the controller is programmed toselect the input of the digital matrix having the lowest power and thecorresponding output of the analog matrix for the nullifying anddecoupling steps, respectively.
 7. The amplifier matrix of claim 1,wherein the controller is programmed to assert an alarm upon detecting afault in the matrix clusters.
 8. A computer-readable storage medium inan amplifier matrix comprising a plurality of matrix clusters,comprising computer instructions for: detecting a fault in anamplification path of one of the matrix clusters; and updating vectorrelationships in the matrix clusters to minimize inter-sector isolationat the outputs of the matrix clusters.
 9. The storage medium of claim 8,wherein each matrix cluster comprises: a digital matrix; a plurality ofup-converters coupled to the outputs of the digital matrix; a pluralityof amplifiers coupled to the outputs of the up-converters; and an analogmatrix coupled to the outputs of the plurality of amplifiers.
 10. Thestorage medium of claim 9, wherein the amplifier matrix comprises aplurality of antennas coupled to the outputs of the analog matrix forradiating signals to a plurality of selective call radios (SCRs). 11.The storage medium of claim 10, comprising computer instructions for:decoupling an antenna from one of the outputs of the analog matrix ofthe affected matrix cluster; and applying a load to said decoupledoutput.
 12. The storage medium of claim 11, comprising computerinstructions for nullifying an input of the digital matrix correspondingto the decoupled output.
 13. The storage medium of claim 12, furthercomprising computer instructions for selecting the input of the digitalmatrix having the lowest power and the corresponding output of theanalog matrix for the nullifying and decoupling steps, respectively. 14.The storage medium of claim 8, comprising computer instructions forasserting an alarm upon detecting a fault in the matrix clusters.
 15. Abase station, comprising: a controller; a receiver; and a transmitter,comprising: an amplifier matrix comprising a plurality of inter-coupledmatrix clusters; and a plurality of antennas coupled to the outputs ofthe amplifier matrix for radiating message signals to selective callradios (SCRs); wherein the controller is programmed to: detect a faultin an amplification path of one of the matrix clusters; update vectorrelationships in the matrix clusters to minimize inter-sector isolationat the outputs of the matrix clusters; and radiate signals from thetransmitter to one or more SCRs.
 16. The base station of claim 15,wherein each matrix cluster comprises: a digital matrix; a plurality ofup-converters coupled to the outputs of the digital matrix; a pluralityof amplifiers coupled to the outputs of the up-converters; and an analogmatrix coupled to the outputs of the plurality of amplifiers.
 17. Thebase station of claim 16, wherein the controller is programmed to:decouple an antenna from one of the outputs of the analog matrix of theaffected matrix cluster; and apply a load to said decoupled output. 18.The base station of claim 17, wherein the controller is programmed tonullify an input of the digital matrix corresponding to the decoupledoutput.
 19. The base station of claim 18, wherein the controller isprogrammed to select the input of the digital matrix having the lowestpower and the corresponding output of the analog matrix for thenullifying and decoupling steps, respectively.
 20. The base station ofclaim 15, wherein the controller is programmed to assert an alarm upondetecting a fault in the matrix clusters.